In regards to dredge decks. Is it safe to assume that you can take out Dredgers and put in some Once Upon a Time in place of those dredgers since it will find dredgers or and additional Bazaar of Baghdad?

You are not casting them with mana, so unless you open with one after a bazaar they are just pitch fodder, unless riftstone portal falls in to favor in a big way.

I suspect the only time you take a dredger with these is actually when you whiff on finding another bazaar, so no I do not think you can cut dredgers in any substantial number to accommodate this as a matter of fact you likely want to keep the count high enough to ensure you hit one if you whiff on bazzar in the first place.

A 2nd Leyline is literally a duplicitous effect or Bazaar fodder. The only thing a 2nd one dies is guard from single target removal (and FoV hits 2). There are few cards with lower value. This is not one of them.

A 2nd Leyline is literally a duplicitous effect or Bazaar fodder. The only thing a 2nd one dies is guard from single target removal (and FoV hits 2). There are few cards with lower value. This is not one of them.

Well, I don't generally plan to generate 1G, so maybe we have a little bit of a different framing here

If Once upon a time was White or Red I think it would be stone unplayable in vintage. Black could be fringe because the decks sometimes make black mana or play unmask/contagion. As a green card, or if it was blue, the fact that it pitches is a substantial part of the sales pitch.